Re: [PATCH v2 1/4] iio: adc: ltc2309: Introduce chip_info structure

[Andy Shevchenko]

On Tue, Mar 24, 2026 at 03:13:28PM +0800, Carlos Jones Jr wrote:
> Introduce a chip_info structure to facilitate adding support for
> chip variants with different channel configurations and timing
> requirements.
> 
> The chip_info structure contains:
> - Device name for proper sysfs identification
> - Channel specifications and count
> - Read delay timing for variants requiring settling time
> 
> The ltc2309 struct is modified to store only the read_delay_us value
> rather than a pointer to the full chip_info, as this is the only
> runtime-accessed field after probe.
> 
> This preparatory refactoring does not modify existing LTC2309
> functionality.

...

>  #include <linux/bitfield.h>
> +#include <linux/delay.h>
>  #include <linux/i2c.h>
>  #include <linux/iio/iio.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/mutex.h>
>  #include <linux/regulator/consumer.h>

> +#include <linux/array_size.h>

It starts with 'a'...

...

> +struct ltc2309_chip_info {
> +	const char *name;
> +	unsigned int num_channels;
> +	const struct iio_chan_spec *channels __counted_by_ptr(num_channels);
> +	unsigned int read_delay_us;

Now on some architectures this might have gaps. Have you run `pahole`?
Even if it's fine, I would rather see

	const char *name;
	const struct iio_chan_spec *channels __counted_by_ptr(num_channels);
	unsigned int num_channels;
	unsigned int read_delay_us;

OR (if there are limitations of __counted_by_ptr() attribute)

	const char *name;
	unsigned int read_delay_us;
	unsigned int num_channels;
	const struct iio_chan_spec *channels __counted_by_ptr(num_channels);

> +};

...

> +static const struct ltc2309_chip_info ltc2309_chip_info = {
> +	.name = "ltc2309",
> +	.num_channels = ARRAY_SIZE(ltc2309_channels),
> +	.channels = ltc2309_channels,
> +};
> +
> +

One blank line too many.

...

>  static int ltc2309_probe(struct i2c_client *client)
>  {
>  	struct iio_dev *indio_dev;
>  	struct ltc2309 *ltc2309;
> +	const struct ltc2309_chip_info *chip_info;

Try to preserve reversed xmas tree order.

>  	int ret;

-- 
With Best Regards,
Andy Shevchenko